This is a mix. On the one hand the drawing itself is cute, well proportioned, and well shaded. Scarily, it may even be in character since Trixie, even in her current about face, does seem like the type to do something unconventional that she thinks would be a good idea or "cool," but may not be. Still, that costume has got to be home made, since I can't see any other character (unless a changeling is disguise?) willing to design that type of thing.

On the other hand... Chrysalis would likely have made a strong impression on Ponyville and Equestria. Dressing up as her would attract attention... and not the positive kind. That is, it can be seen someone asking her "You a changeling sympathizer?" That might not end all that well. Then again, this is Trixie, so she probably would say something that would convince that type of person that she really is intending this from an innocuous angle (I hope).

Holy fritters... the cuteness. I'm pretty sure something of this magnitude is illegal and I'm going to have to report this to the proper governmental agencies.

But before I do so, allow me to compliment the genius that is her costume. Having her dress as Chrysalis was great enough, but adding the black paint marks to represent the leg holes? The cute, little fangs? Her candy bag having her cutie mark on it? And... and... look at that excited face!

Not aimed at you, more of a general-announcement to the whole fandom that seem to hold even monsters like Sombra in higher regard than the banevolant, self-sacrifical demi-god that is written to be loved.

I think it's because Celestia is too perfect in the series. If they would add some serious flaws personality flaws of Celestia (that she admits to) then I would think Celestia would be a lot more popular. She doesn't have flaws so people think them up themselves and then get a bit too caught up in it.